5 Soluciones: Factores importantesPrecioPrecisión v CoberturaNecesidades diferentes en el caso de situaciones no críticasLugares distintos – en una ciudad, dentro de un edificioErgonomíaConsumo de energía eléctricaMomento de lanzamiento del producto¿Solución estándar o propietaria?¿Puede TETRA soportar la solución?Soporte de la red y requerimientos de ancho de bandaFor the hand-held terminal, the following criteria has to be met.Price – does the benefit of having location outweigh its cost? What price do you put on the life of the user?Does it provide the desired level of accuracy in every area required?Does it ‘fit well’ with existing product. Is it easy to hold, use etc.In the case of a personal carried device, what is its effect on battery life?Is it available today. How long to implement solution?Standard or proprietary solutions. Do you want to be locked in to one solution?Does the solution function over TETRA!

6 Requerimientos de Mando & ControlManejo eficiente de recursosRequerimientos de APLS no son iguales a AVLSLos usuarios no deben sentirse amenazados por APLS (Privacidad)Detalles de actualización de posición fijados en el caso de varias tareasCombinación de varios sistemas/bases de datos para dar al oficial aviso previo de peligroC&C have its own list of requirements.Numbers of users will increase. How does this increase in traffic get managed?User needs to feel that the system is not intruding upon their privacy.Does the hand-held solution provide functionality that the C&C can make use of in manipulating dataWhat about integration of mapping applications into full C&C systems?Next few slides demonstrates the problem!

7 Manejo de Recursos - AVLSTraditional mapping systems adequate for showing position of vehicles. Typically number of users at any time in order of 10’s

8 Manejo de Recursos - APLSWith the increase use of person location, numbers of users at any time increase by many orders of magnitudes. Imagine an operator faced with making decisions based on this scenario!

9 Manejo de Recursos – con técnicas de filtraciónBy managing the data both from the user and that displayed at the mapping application, makes the decision process much easier. Finding the correct resources available to quickly assist in an emergency situation.

10 Soluciones de Localización y Rendimiento ComparativoSoluciones de precisión baja y de bajo costoDiferencia de tiempo de llegada (Time difference of arrival – TDOA)Diferencia de tiempo observado mejorado (Enhanced observed time difference – EOTD)Soluciones de precisión mediana y de costo medianoGPS estándarGPS asistido (Assisted GPS, A-GPS)GPS con señales de baja intensidadSoluciones de alta precisión y de alto costoGPS diferencialCombinaciones de solucionesThe slide shows the current technologies available to the customer.Selection of a suitable location technology depends upon answers to various questions. These include,What is the normal operating environment of user?What is the level of accuracy required?How much is the customer prepared to pay?.In the examples earlier of E911, the end user (cellular phone user) is not prepared to pay extra for a location system that they may never use!

11 Soluciones de precisión baja y de bajo costo (terminales)Diferencia de Tiempo de Llegada (Time Difference Of Arrival TDOA)muy costosa su implementación en la redprecisión de +/- 500 metrosDiferencia de Tiempo Observado Mejorado (Enhanced Observed Time Difference - EOTD)bajo costo, sin soporte de la estación base según sus desarrolladoresprecisión de 200m a 2kmAmbas tecnologíasTienen una buena penetración dentro de edificios y en ciudades, pero con una precisión bastante pobre – un criterio determinante para soluciones basadas en redes donde la precisión de localización puede ser críticaOcupan mucho ancho de banda, y no son soluciones aptas para TETRATypically used alongside cellular phones, both systems are based on having an overlay system that can make signal strength measurements and process using triangulation techniques to provide a location – see next slide.In the case of EOTD, Cambridge Positioning Systems are claiming that their solution does not require additional processing at the base station and uses additional hardware present at the radio.Both technologies have good indoor/urban canyon penetration, but with very poor accuracy - a general show stopping issue for network based solutions where location accuracy could be critical. Also, both tend to be bandwidth hungry and therefore not suitable for TETRA

12 Soluciones Basadas en RedesLMURadio towerServidorTETRAAplicaciónGIS o deMapeoGatewaySoluciones Basadas en RedesPrecisión Actual = 200m - 2kmPrecisión Futura = mExample showing measurements of received signals from the radio. The time taken to receive at each site is used to estimate locationThe radio’s signal is received at various antenna sites.Since each antenna is a (usually) different distance from the caller, the signal arrives at a (very) slightly different time. The technique requires signal timing information from at least three different antenna sites.The receivers, synchronized by an atomic clock, send the caller's voice call and timing data on to the mobile switch, where the times are compared and computed to generate a latitude and longitude for the caller. Data then sent along to the C&C for plotting onto a map.

13 Soluciones de precisión mediana y de costo medianoGPS estándartiempo para lograr primeros datos (fix) igual a 3 minutosprecisión de >30 metros, sin cobertura en edificios y entre edificios altosGPS asistido (A-GPS)tiempo para lograr primeros datos (fix) igual a 30 segundosprecisión de >30 metrosGPS con Señales de Baja Intensidad (alta sensibilidad)tiempo para lograr primeros datos (fix) es normalmente de 45 segundosprecisión de <30 metroscobertura en edificios y entre edificios altosNota: todas estas soluciones tienen una precisión de localización de <10 metros en el 95% de los casos en campo abiertoStandard GPS devices have been used for vehicle location for many years. The use of an active antenna helps with signal detection when used in towns/city environments thus improving the overall availability and accuracy.Assisted GPS (A-GPS), takes much of the location processing away from the radio and places this at the command centre, keeping the cost of radio hardware low.This is the technique currently being employed in a majority of cell phones used in the USA meeting the E911 mandateHigh sensitive GPS receivers becoming available times more sensitive than traditional GPS devicesSince Selective Availability has been removed from the commercial use of GPS, location accuracy can be as good as within a few metres in open spaces.

15 Soluciones de alta precisión y de alto costoGPS diferencialPrecisión en campo abierto a <10 metrosSu implementación es cara y requiere estaciones base diferenciales terrestres y transmisiones regulares de redUsa una red con mucho ancho de bandaCombinaciones de Soluciones (GPS+Radiofaro+Odómetro)Precisión entre metrosSe requiere una red de radiofaros para soportar esta soluciónEnhancements to further improve the accuracy of GPS solutions.Externally this could be by using differential GPS whereby the hand-held receives additional data from very accurately located sites. These ‘sites obtain their position using GPS and work out the difference between measured and actual.The ‘correction data’ is then sent over-air to radios within the network, thus providing them with continuous information that allows them to compensate for satellite ‘wobble’ and atmospheric effects that influence the accuracy of GPS based location systems.Alternately, combinations involving additional ‘kit’ such as gyro’s and linkage to odometer devices allow use of GPS when satellite coverage is restricted.These solution provide better accuracy and coverage but at additional cost.

16 GPS – Alta precisión Red TETRA Aplicación GIS o de Mapeo GatewayTower boxServidorC & CAplicaciónGIS o deMapeoRedTETRAGatewaySDSGPSOdómetroReceptorRadiofarodGPS StationThis slide shows the two cases. In this example, the fixed ground station receives GPS information and then providing compensation data to the radio fleet.Additional devices such as odometers can also be attached to the radio to enhance GPS performance.Using these techniques, location accuracy of within a few metres is achievable

22 Pruebas de Usuario – Comparación entre soluciones GPSProducto AProducto B4 veces mejor en precisión & disponibilidadUna Prueba es esencial!In a recent customer evaluation of the SRP2000 sGPS against competitor products, it was shown that the Sepura radio out performed the competitor by a factor of four in positional accuracy and the number of times that the GPS receiver was able to provide a position.